Browsing by Author "Abu-Hamdeh N.H."

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    Mixed convection due to a rotating cylinder in a 3D corrugated cavity filled with single walled CNT-water nanofluid
    (Springer Science and Business Media B.V., 2019) Selimefendigil F.; Oztop H.F.; Abu-Hamdeh N.H.
    Analysis of mixed convection due to a rotating inner cylinder in a corrugated three-dimensional cavity filled with carbon nanotube-water nanofluid was performed. Numerical simulations were performed by using Galerkin weighted residual finite element method. The three-dimensional corrugated cavity was differentially heated form the vertical surfaces, and an inner rotating adiabatic cylinder was used. Influence of Rayleigh number (between 104 and 106), angular rotational velocity of the cylinder (between − 50 and 50 rad/s), height (between H / 10 and H / 3) and number of triangular waves (between 1 and 16) and solid nanoparticle volume fraction (between 0 and 0.04) on the convective heat transfer characteristics was analyzed. It was observed that average heat transfer augments significantly by changing the nanoparticle volume fraction and up to 128% of enhancement is obtained. Depending on the rotational direction of the cylinder, average Nusselt number enhances 68 % in the three-dimensional cavity. Surface corrugation parameters are not as effective as solid particle volume fraction and angular rotational speed of the cylinder on the heat transfer enhancements. Finally, a correlation for the average Nusselt number along the cold surface was provided which is dependent upon the angular rotational speed of the cylinder and Rayleigh number. © 2018, Akadémiai Kiadó, Budapest, Hungary.
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    Analysis of the Melting Time of Phase Change Material in a Heat Exchanger with Sinusoidal Inner Duct
    (MDPI, 2023) Öztop H.F.; Akbal Ö.; Selimefendigil F.; Abu-Hamdeh N.H.
    Three-dimensional computational analysis has been performed to investigate the melting time of the phase change material (PCM) in a sinusoidal pipe inserted into another pipe. The other pipe is filled with PCM and the system is heated from the inner sinusoidal pipe at different temperatures. The main aim of the study is to control the melting time. The finite volume method (FVM) is used to solve time-dependent governing equations. Four different cases are chosen for the sinusoidal wall to see the effects of geometry on melting. After the analysis, it is observed that melting time can be controlled via an adjustment of the geometrical parameter, namely a passive technique, without spending extra energy. © 2023 by the authors.
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    A Review on Non-Newtonian Nanofluid Applications for Convection in Cavities under Magnetic Field
    (MDPI, 2023) Selimefendigil F.; Şenol G.; Öztop H.F.; Abu-Hamdeh N.H.
    This review is about non-Newtonian nanofluid applications for convection in cavities under a magnetic field. Convection in cavities is an important topic in thermal energy system, and diverse applications exist in processes such as drying, chemical processing, electronic cooling, air conditioning, removal of contaminates, power generation and many others. Some problems occur in symmetrical phenomena, while they can be applicable to applied mathematics, physics and thermal engineering systems. First, brief information about nanofluids and non-Newtonian fluids is given. Then, non-Newtonian nanofluids and aspects of rheology of non-Newtonian fluids are presented. The thermal conductivity/viscosity of nanofluids and hybrid nanofluids are discussed. Applications of non-Newtonian nanofluids with magnetohydrodynamic effects are given. Different applications of various vented cavities are discussed under combined effects of using nanofluid and magnetic field for Newtonian and non-Newtonian nanofluids. The gap in the present literature and future trends are discussed. The results summarized here will be beneficial for efficient design and thermal optimization of vented cavity systems used in diverse energy system applications. © 2022 by the authors.